The second illusion is very like the first, so if you’ve seen the first, the second is nothing special. Also, there isn’t much illusion with the second one. It’s pretty obvious that the legs aren’t the girl’s own legs!

I doubt sexual orientation is as big a factor on spotting this ilusion. Rather, I suspect it’s that many men here, when they are looking at the picture of a woman on the internet, like as not it’s porn. Ergo men are predisposed to seeing photos of women viewed on the internet as probably pornographic.,
Obviously not all pictures of any woman. Just usually young, attractive ones with a lot of skin-tone in the picture.

so, it’s not that men are predisposed to seeing it but that it’s viewed via the medium of the Internet, where this sort of picture is commonplace.
(I’m female)

Legion-I think I was fairly clear about the “illusion”. It looks like you can see a woman’s pants (or underwear for those in US). Despite this sight being fairly common in swimming pools, beaches etc, some men seem to find it thrilling if it’s seen in a car or on the front page of a newspaper.